Multi-component aqueous cleaning compositions are widely used throughout industry. The cleaning chemical industry has traditionally employed large scale processes to manufacture dilute aqueous cleaners which are then shipped to customers' use locations. Obviously, the transportation of dilute aqueous compositions involves the movement of large volumes of dilute aqueous products which are predominantly water. It is recognized that significant savings in transportation expenses can be achieved if the cleaning compositions could be moved in a concentrated form. Thus, the cleaning chemical industry has begun supplying cleaning chemical concentrates to use locations.
Unfortunately, the users of these cleaners may not recognize the importance of proper dilution ratios of the cleaners or may not be capable of accurately forming the proper dilutions. This may result in the use of dangerously concentrated cleaning compositions or ineffectively or inefficiently diluted compositions at the cleaning site. In any event, it is difficult for the suppliers of the chemical concentrates to warrant their products without control of the often critical dilution step.
In addition, while many similar cleaning compositions have identical chemical components, their relative proportions may be different in the diluted cleaning product. Therefore, the producers of concentrated cleaning compositions must offer numerous cleaning concentrates for the various cleaning needs of a customer. Thus, the customer is left with storage areas which may become cluttered and confused with numerous similar cleaning concentrates which may be mistakenly selected and applied in an improper manner.
To overcome the above hazards and limitations, manufacturers of cleaning compositions have discovered methods of enabling their customers to produce dilute aqueous chemical cleaning compositions at their own plants. These methods usually employ some apparatus which prepares a variety of cleaning compositions from chemical concentrate tanks and a water supply. Often, these apparatus are microprocessor controlled so the supplier can program the preparation of cleaning compositions which are individually tailored for the particular customer's needs. Examples of such dispensers include portable devices as disclosed in Smith, U.S. Pat. No. 3,797,744, and mounted devices as disclosed in Kirschmann et al., U.S. Pat. No. 4,691,850; Marty et al., U.S. Pat. No. 4,941,596; Turner et al., U.S. Pat. No. 5,014,211; and Decker et al., U.S. Pat. No. 4,976,137.
The Smith patent discloses a portable cleaning and sanitizing system comprising a plurality of pressurized chemical component tanks which are connected to a manifold and conducted to a spray nozzle. The outlet of each component tank passes under pressure through a three-way valve, metering valve, flow indicator and control valve prior to entry into the manifold. The chemical components are delivered at various points along the length of the manifold. However, this system is designed for use in sequentially delivering a plurality of cleaning compositions prepared by concurrently withdrawing and diluting the chemical components. The system meters and controls the flow of individual chemical components to continuously form the cleaning spray.
The Kirschmann patent discloses a time-based chemical dispensing system comprising two manifolds and a pump to draw the chemical components through a distribution manifold. Valves are positioned to allow the pump to draw one chemical at a time through the distribution manifold for a specified time. The chemical is then delivered through an outlet manifold and to a container. Water is also delivered through the outlet manifold to make up the aqueous composition. Both manifold in the system are flushed after each chemical is dispensed, and the chemical input ports are arranged along the length of the manifold.
The Marty patent discloses a volume-based mixing system for use with concentrated liquids comprising a mixing manifold connected to a positive displacement pump. In the operation of this system, the manifold passageway is filled with water, a chemical concentrate supply valve to the manifold is opened, and the pump is operated to draw a predetermined amount of water or carrier fluid from the manifold, drawing an equal volume of chemical concentrate into the manifold. The pump is operated for a given number of cycles to deliver a specified volume of chemical concentrate. This system further comprises a pressure regulator to maintain a predetermined pressure on the water or carrier fluid to allow for control of the system. Again, the chemical concentrate inlet ports are arranged along the length of the manifold.
The commonly assigned Decker patent discloses a chemical mixing and dispensing system comprising a manifold having a plurality of chemical component inlet ports arranged along the length of the manifold. There are a plurality of chemical component supply pumps and valves for delivering the chemical components to the manifold under pressure. To provide quality control of the system, there are conductivity sensors, a weight measurement device at the filling station and electronic control means.
The Turner patent discloses a wash chemical dispenser delivery system employing a linear manifold for delivering a series of diluted chemicals to selected laundry machines in a network. Cleaning compositions are formed within the tub of each individual machine. There is a three-way valve located at each machine to control delivery to or bypass of the particular machine. Metering pumps deliver individual chemical concentrates to the manifold where they are simultaneously diluted with water, and these pumps are calibrated through a conductivity cell located downstream of the manifold. Quality control is obtained using proof of flow and proof of delivery conductivity meters at the outlet of the manifold and at the valves which deliver the chemicals to each machine. This device is time-based, in that delivery of the chemical concentrates is controlled by the time of operation of the metering pumps.
While the above dispensing systems are useful in many applications, each particular apparatus design incorporates compromises between competing functions and controls. Thus, new dispensing systems are constantly needed which can offer particular advantages in particular applications having given operating requirements. The prior art discloses a number of different dispensing systems having particular geometries and control systems. However not one of these references teaches a dispenser having redundant time- and flow-based operating controls. Further, the dispensing systems discussed above have use under particular operating conditions, but not one of the references teaches a dispensing system which has time- and flow-based controls and is accurately operable to produce a wide variety of cleaning compositions over a large volume range.